// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/snapshot/startup-deserializer.h"

#include "src/api.h"
#include "src/assembler-inl.h"
#include "src/heap/heap-inl.h"
#include "src/snapshot/snapshot.h"
#include "src/v8threads.h"

namespace v8 {
namespace internal {

    void StartupDeserializer::DeserializeInto(Isolate* isolate)
    {
        Initialize(isolate);

        if (!allocator()->ReserveSpace()) {
            V8::FatalProcessOutOfMemory(isolate, "StartupDeserializer");
        }

        // No active threads.
        DCHECK_NULL(isolate->thread_manager()->FirstThreadStateInUse());
        // No active handles.
        DCHECK(isolate->handle_scope_implementer()->blocks()->empty());
        // Partial snapshot cache is not yet populated.
        DCHECK(isolate->partial_snapshot_cache()->empty());
        // Builtins are not yet created.
        DCHECK(!isolate->builtins()->is_initialized());

        {
            DisallowHeapAllocation no_gc;
            isolate->heap()->IterateSmiRoots(this);
            isolate->heap()->IterateStrongRoots(this, VISIT_FOR_SERIALIZATION);
            Iterate(isolate, this);
            isolate->heap()->IterateWeakRoots(this, VISIT_FOR_SERIALIZATION);
            DeserializeDeferredObjects();
            RestoreExternalReferenceRedirectors(accessor_infos());
            RestoreExternalReferenceRedirectors(call_handler_infos());

            // Flush the instruction cache for the entire code-space. Must happen after
            // builtins deserialization.
            FlushICache();
        }

        isolate->heap()->set_native_contexts_list(
            ReadOnlyRoots(isolate).undefined_value());
        // The allocation site list is build during root iteration, but if no sites
        // were encountered then it needs to be initialized to undefined.
        if (isolate->heap()->allocation_sites_list() == Smi::kZero) {
            isolate->heap()->set_allocation_sites_list(
                ReadOnlyRoots(isolate).undefined_value());
        }

        isolate->builtins()->MarkInitialized();

        LogNewMapEvents();

        if (FLAG_rehash_snapshot && can_rehash()) {
            // Hash seed was initalized in ReadOnlyDeserializer.
            Rehash();
        }
    }

    void StartupDeserializer::LogNewMapEvents()
    {
        if (FLAG_trace_maps)
            LOG(isolate_, LogAllMaps());
    }

    void StartupDeserializer::FlushICache()
    {
        DCHECK(!deserializing_user_code());
        // The entire isolate is newly deserialized. Simply flush all code pages.
        for (Page* p : *isolate()->heap()->code_space()) {
            FlushInstructionCache(p->area_start(), p->area_end() - p->area_start());
        }
    }

} // namespace internal
} // namespace v8
